Objective - evaluate horses with acute airway obstruction using three treatment regimens: tapering doses of dexamethasone (DEX), environmental modification (ENV), and a combination of both treatments (DEX + ENV) by analyzing clinical parameters, pulmonary function testing, bronchoalveolar lavage fluid (BALF) cytology and BALF cell expression of the cytokines IFN-? and IL-4
Animals - 6 horses with recurrent airway obstruction (RAO)
Procedures - Clinical examination, pulmonary function test, and collection of BALF prior to treatment and during 22 day treatment period
Hypothesis - Alterations in clinical parameters, pulmonary function and airway inflammation in acute equine RAO will return to remission values by treating with DEX, ENV or DEX + ENV
Results - All horses demonstrated clinical disease, reduced pulmonary dynamic compliance (Cdyn) and an increased maximum change in pleural pressures (?Pplmax) when in a challenge environment. All treatments improved clinical parameters, ?Pplmax and Cdyn. BALF cytology during an RAO crisis demonstrated neutrophilic inflammation. ENV or DEX + ENV resulted in a significant decrease in airway neutrophilia that was maintained throughout the treatment period. In contrast, treatment with DEX caused a reduction in airway neutrophilia initially followed by a rebound neutrophilia as the period between administrations of dexamethasone (0.05mg/kg) was increased to 72 hours. The rebound neutrophilia was not accompanied by equivalent deterioration in clinical parameters or pulmonary function.
Conclusions - Environmental modification is important in the management of RAO horses. Treatment of clinical RAO with a decreasing dosage protocol of corticosteroids in the absence of environmental modification results in the persistence of airway inflammation without recrudescence of clinical disease. / Master of Science
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/76818 |
| Date | 17 August 2009 |
| Creators | Lee, Laura Caryn |
| Contributors | Veterinary Medical Sciences, Zimmerman, Kurt L., Witonsky, Sharon G., Buechner-Maxwell, Virginia A. |
| Publisher | Virginia Tech |
| Source Sets | Virginia Tech Theses and Dissertation |
| Language | en_US |
| Detected Language | English |
| Type | Thesis, Text |
| Format | application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
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